Problem: In her math class, Tiffany took 6 tests. Her scores were 85, 92, 87, 90, 75, and 87. What was her average score on the tests?
Explanation: The average is the sum of her scores divided by the number of scores. There are 6 scores and their sum is $85 + 92 + 87 + 90 + 75 + 87 = 516$ Her average score is $516 \div 6 = 86$.